isZero {R.utils} | R Documentation |
Checks if a value (or a vector of values) is (close to) zero or not
where "close" means if the absolute value is less than neps*eps
.
Note that x == 0
will not work in all cases.
By default eps
is the smallest possible floating point value
that can be represented by the running machine, i.e.
.Machine$double.eps
and neps
is one.
By changing neps
it is easy to adjust how close to zero "close"
means without having to know the machine precision (or remembering how
to get it).
## Default S3 method: isZero(x, neps=1, eps=.Machine$double.eps, ...)
x |
A vector of values. |
eps |
The smallest possible floating point. |
neps |
A scale factor of eps specifying how close to zero
"close" means. If eps is the smallest value such that
1 + eps != 1 , i.e. .Machine$double.eps , neps must
be greater or equal to one. |
... |
Not used. |
Returns a logical
vector
indicating if the elments are zero or not.
Henrik Bengtsson (http://www.braju.com/R/)
x <- 0 print(x == 0) # TRUE print(isZero(x)) # TRUE x <- 1 print(x == 0) # FALSE print(isZero(x)) # FALSE x <- .Machine$double.eps print(x == 0) # FALSE print(isZero(x)) # FALSE x <- 0.9*.Machine$double.eps print(x == 0) # FALSE print(isZero(x)) # TRUE